1. Field of the Invention
The present invention relates generally to architectural renderings, and in particular, to a method, apparatus, and article of manufacture for filling a shape to achieve a natural hand-drawn effect in an architectural rendering.
2. Description of the Related Art
In the architectural, engineering, and construction (AEC) fields, computer aided design (CAD) drawings are often used to design blueprints, drawings, plans, etc. However, such CAD drawings may be complex, confusing, and fail to provide an end-user (e.g., a potential client) with a drawing or visualization of the “intent” of the architect or designer. Architectural renderings are designed to illustrate the “intent” of the designer or architect, as opposed to showing precise fidelity. In these renderings, the illustrator may want the inside of an object (referred to as fill) to appear natural. In the prior art, such object fill usually consists of a solid/transparent color, an image, or a pattern. In this regard the prior art techniques fail to achieve a hand-drawn look of natural art tools. Such problems may be better understood with a description of prior art drawing software and methodologies.
CAD programs provide high fidelity drawings that fail to provide a visualization of the intent of the user. Such CAD programs or other drawing programs may be vector-based or raster-based. It may be possible to achieve hand-drawn effects in raster-based drawing programs. For example, in a raster-based program, a bitmap stroke may be created that appears hand-drawn (e.g., using a variety of raster-based drawing/paint tools). However, it may be preferable to work in a vector-based drawing. For example, in vector-based drawing programs, a user may work with modifiable shapes that can be edited, resized, and rearranged. Nonetheless, the inherent mathematical description of vector shapes lends itself to the production of hard-edged, non-organic artwork. Thus, it has always been a challenge for digital artists to achieve natural hand-drawn effects in a vector-based drawing program.
There are a number of domains, architecture being one, where there is a need to be able to create natural-looking renderings of (inherently) geometric hard-edged drawings. In this regard, architectural renderings may take a variety of forms or styles, from hand-drawn renderings, to cartoon-like rendering, to ultra-realistic 3D rendering. In an architectural rendering, it's less important to be geometrically accurate, and more important for the drawing to be able to evoke the “spirit/goals” of the project.
While the prior art has attempted to create vector-based strokes that appear organic, the prior art has failed to make object fills appear natural. For example, prior art programs may attempt to fill an object utilizing a single Bezier curve that wraps back and forth from one side of a shape to the next. Such a technique utilizes a single stroke and does not appear authentic or hand-drawn. Instead, the single Bezier curve appears computer generated. Another prior art technique may define a shape using a Bezier curve and utilize the defined shape as the paint stroke. For example, if a rectangle is defined, as the user draws the stroke and presses harder (e.g., using a stylus and tablet device), the rectangle deforms in relation to the pressure. However, the shape or stroke or pressure cannot be modified after it is drawn.
In view of the above, fills, in general, are typically either solid/transparent color, images or patterns. Such prior art fill techniques fail to achieve an easy, intuitive, vector-based modifiable means for providing a hand-drawn look of natural art tools.
Accordingly, what is needed is a way to create a modifiable vector fill in a object-based drawing program that simulates natural-media techniques.